ArmPlatformPkg: Unify the Secure and Normal FD and FV PCD naming

ArmPlatformPkg: Unify the Secure and Normal FD and FV PCD naming

With this change, we now have these following PCDs values to define the
location of the Secure and Normal firmwares:
- gArmTokenSpaceGuid.PcdSecureFd(BaseAddress|Size)
- gArmTokenSpaceGuid.PcdSecureFv(BaseAddress|Size)
- gArmTokenSpaceGuid.PcdNormalFd(BaseAddress|Size)
- gArmTokenSpaceGuid.PcdNormalFv(BaseAddress|Size)

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11806 6f19259b-4bc3-4df7-8a09-765794883524